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Moistened Seeds Increase Rodent Trap Success, John C. Tull, Michael W. Sears
Moistened Seeds Increase Rodent Trap Success, John C. Tull, Michael W. Sears
Western North American Naturalist
Seed moisture has been shown to influence the rates of seed cache removal by rodents. Although the precise mechanism is not known, this knowledge might prove useful in field applications. We examined whether moistened bait would increase trap success in desert rodent populations. We placed traps 15 m apart in grids within a 500-ha study area and randomly baited traps with either dry or moistened seeds. We found that traps baited with moistened seeds had 34.9% higher success than traps baited with dry seeds (n = 190, χ2 = 5.389, df = 1, P = 0.020). Our results …
Seasonality And Fidelity In Roost Use Of The Mexican Free-Tailed Bat, Tadarida Brasiliensis, In An Urban Setting, Jeffrey A. Scales, Kenneth T. Wilkins
Seasonality And Fidelity In Roost Use Of The Mexican Free-Tailed Bat, Tadarida Brasiliensis, In An Urban Setting, Jeffrey A. Scales, Kenneth T. Wilkins
Western North American Naturalist
We studied 7 urban roosts occupied by Mexican free-tailed bats (Tadarida brasiliensis) in downtown Waco, Texas, from August 2001 to September 2002. We examined frequency of roost use, colony sizes, and roost fidelity in relation to gender. Use of roosts and colony sizes were highest in the fall and lowest in the winter, but fluctuated widely during the study. These roosts were not used by maternity colonies, and patterns of occupancy suggested that they served as stopover sites during migratory seasons. Individual bats exhibited high fidelity to discrete roosts included in the study. However, the bats commonly left …
Roadside Foraging By Kangaroo Rats In A Grazed Short-Grass Prairie Landscape, Paul Stapp, Mark D. Lindquist
Roadside Foraging By Kangaroo Rats In A Grazed Short-Grass Prairie Landscape, Paul Stapp, Mark D. Lindquist
Western North American Naturalist
We used live-trapping and foraging experiments to describe use of roadside vegetation by kangaroo rats (Dipodomys ordii) in short-grass prairie in Colorado, and to determine whether this species' perception of predation risk differed between roadside habitats, where predators were expected to be most active, and locations 120 m into adjacent grazed pastures. Giving-up densities (GUDs) were measured in paired seed trays placed beneath saltbush (Atriplex canescens) shrubs and in the open, 3 m from shrubs along transects in roadside and pasture locations. Trials were conducted on nights with a partial (1st-quarter), full, and new moon to …
Changes In Kit Fox–Coyote–Prey Relationships In The Great Basin Desert, Utah, Wendy M. Arjo, Eric M. Gese, Tim J. Bennett, Adam J. Kozlowski
Changes In Kit Fox–Coyote–Prey Relationships In The Great Basin Desert, Utah, Wendy M. Arjo, Eric M. Gese, Tim J. Bennett, Adam J. Kozlowski
Western North American Naturalist
Variation in kit fox (Vulpes macrotis) population parameters can be influenced by vegetative cover and the distribution and abundance of other predator and prey species. Dramatic changes to Great Basin Desert habitats, which can potentially impact mammalian species, have occurred in some areas in Utah. We examined kit fox demographics and prey populations from 1999 to 2001 on Dugway Proving Ground (DPG), a U.S. Army facility in Utah, and compared some parameters to historical levels (1956–1958, 1966–1969). Adult survival rates were fairly consistent between 1999 and 2000 and between 1999 and 2001; however, survival was greater in 2001 …
Effects Of Exotic Grasses On Soil Seed Banks In Southeastern Arizona Grasslands, Steven P. Mclaughlin, Janice E. Bowers
Effects Of Exotic Grasses On Soil Seed Banks In Southeastern Arizona Grasslands, Steven P. Mclaughlin, Janice E. Bowers
Western North American Naturalist
At the Appleton-Whittell Research Ranch, an ungrazed grassland preserve in southeastern Arizona, soil seed banks were sampled in June, August, and October 2002 and June 2003. Wildfire had previously burned 90% of the research ranch in May 2002. Seed density and species richness in burned native grassland (2 plots) were compared to those in burned exotic grassland (2 plots). Averaged over 4 sample dates, seed densities were as follows: burned native grassland, 591 ± 243.1 seeds · m−2 and 784 ± 334.9 seeds · m−2; burned exotic grassland, 501 ± 198.9 seeds · m−2 and 196 …
Use Of Agricultural Lands By San Joaquin Kit Foxes, Gregory D. Warrick, Howard O. Clark Jr., Patrick A. Kelly, Daniel F. Williams, Brian L. Cypher
Use Of Agricultural Lands By San Joaquin Kit Foxes, Gregory D. Warrick, Howard O. Clark Jr., Patrick A. Kelly, Daniel F. Williams, Brian L. Cypher
Western North American Naturalist
Although the current range of the endangered San Joaquin kit fox (Vulpes macrotis mutica) borders large areas of farmland, the ecology of this species rarely has been studied within an agricultural setting. In central California, we examined habitat use, prey availability, and diet of radio-collared kit foxes inhabiting an aqueduct right-of-way (ROW) bordered by farmland. During both years of study (1998–1999), nocturnal locations of foxes occurred more often than expected (based on habitat availability) in the ROW and less often than expected within annual crops. Orchards were used disproportionately more than their availability during 1998 and were used …
Dispersal And Extraterritorial Movements Of Swift Foxes (Vulpes Velox) In Northwestern Texas, Kerry L. Nicholson, Warren B. Ballard, Brady K. Mcgee, Heather A. Whitlaw
Dispersal And Extraterritorial Movements Of Swift Foxes (Vulpes Velox) In Northwestern Texas, Kerry L. Nicholson, Warren B. Ballard, Brady K. Mcgee, Heather A. Whitlaw
Western North American Naturalist
Dispersal plays an important role in the population dynamics of many carnivores, yet little information exists about the dispersal and movement patterns of swift foxes (Vulpes velox). We radio-collared and monitored 68 swift foxes for dispersal at 2 study sites in northwestern Texas from January 2002 to April 2004. Dispersal distance for juveniles (13.1 ± 0.3 km, s), adults (10 ± 4.7 km) and transients (25.4 ± 9.1 km) did not differ by age class (F = 1.49, df = 2, P = 0.24) or sex (F = 0.23, df = 1, P = 0.63) …
Long-Term Effects Of Tebuthiuron On Bromus Tectorum, Dana M. Blumenthal, Urszula Norton, Justin D. Derner, Jean D. Reeder
Long-Term Effects Of Tebuthiuron On Bromus Tectorum, Dana M. Blumenthal, Urszula Norton, Justin D. Derner, Jean D. Reeder
Western North American Naturalist
Use of herbicides to thin dense stands of Artemisia spp. (sagebrush) can free up resources for herbaceous plants and increase forage production, but may also facilitate weed invasion. We revisited a sagebrush thinning experiment in a north central Wyoming big sagebrush–grassland 11 years after application of tebuthiuron (N-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-N-N′-dimethylurea) to determine the long-term responses of shrubs, available soil resources, perennial grasses, and Bromus tectorum L. (downy brome). Tebuthiuron reduced shrub cover by more than half, from 31% in untreated plots to 15% in treated plots (P = 0.002), and increased downy brome cover approximately 4-fold, from 0.9% in untreated plots …
Plant Composition And Erosion Potential Of A Grazed Wetland In The Salmon River Subbasin, Idaho, Kristine N. Hopfensperger, Joan Q. Wu, Richard A. Gill
Plant Composition And Erosion Potential Of A Grazed Wetland In The Salmon River Subbasin, Idaho, Kristine N. Hopfensperger, Joan Q. Wu, Richard A. Gill
Western North American Naturalist
Wetlands are dynamic habitats with many unique, important functions including filtering sediments and providing diverse habitats for fish and wildlife. Wetlands in the western United States are particularly important because they offer habitat for a number of protected runs of endangered fish species. Historically, livestock grazing has altered wetland and riparian area form and function by facilitating exotic species invasions, altering spatial heterogeneity of vegetation, and increasing erosion. In this study we examined vegetation structure and erosion potential in a wetland meadow exposed to unregulated grazing along Deer Creek in the Salmon River subbasin, Idaho. We characterized the vegetation composition …
Tamarix Aphylla: A Newly Invasive Tree In Southern Nevada, Lawrence R. Walker, Pamela L. Barnes, Elizabeth A. Powell
Tamarix Aphylla: A Newly Invasive Tree In Southern Nevada, Lawrence R. Walker, Pamela L. Barnes, Elizabeth A. Powell
Western North American Naturalist
In the southwestern United States, the nonnative athel pine (Tamarix aphylla) was presumed to be sterile and therefore not as likely to spread as its widely distributed, nonnative congener, T. ramosissima. However, at Lake Mead National Recreation Area (LMNRA) in southern Nevada, populations of T. aphylla have recently spread beyond their limited pre-1990 distribution and now form extensive monospecific stands. Over a 3-year period, we quantified seed production and germination from 60 T. aphylla trees at LMNRA. The annual mean seed production period was 50.6 days, and the mean potential germination (under laboratory conditions) was 22%, indicating …
The Effect Of Livestock Grazing On The Rainbow Grasshopper: Population Differences And Ecological Correlates, Sandra J. Debano
The Effect Of Livestock Grazing On The Rainbow Grasshopper: Population Differences And Ecological Correlates, Sandra J. Debano
Western North American Naturalist
This study examined the effect of livestock grazing on a common herbivore in semiarid grasslands of the Southwest: the rainbow grasshopper, Dactylotum variegatum. Population attributes and key environmental variables were compared between sites on active cattle ranches and sites on a 3160-ha ungrazed sanctuary. Although density of D. variegatum nymphs did not differ significantly between grazed and ungrazed sites, adult density was significantly lower on grazed sites, and sex ratios differed between grazed and ungrazed sites over time. Grazed sites had higher percentages of bare ground and fewer Baccharis pteronioides, a common shrub. However, only bare ground was …
Characteristics Of Swift Fox Dens In Northwest Texas, Brady K. Mcgee, Kerry L. Nicholson, Warren B. Ballard, Matthew J. Butler
Characteristics Of Swift Fox Dens In Northwest Texas, Brady K. Mcgee, Kerry L. Nicholson, Warren B. Ballard, Matthew J. Butler
Western North American Naturalist
The swift fox (Vulpes velox) was classified in 1995 as a candidate for listing under the Endangered Species Act. Since then, several studies have addressed survey methods for monitoring swift fox populations. The purpose of this paper is to assist field researchers in documenting the presence of swift foxes by identification of recently active den sites. We propose that swift foxes have unique external den characteristics that can be distinguished during aerial surveys. We collected data from 30 swift fox den complexes on both continuous rangeland and landscapes fragmented by cropland in northwest Texas. There were no differences …
Dietary Overlap In Giant Salamanders (Dicamptodon): Applying Null Models To Resource Partitioning, Craig A. Steele, Colin Brammer
Dietary Overlap In Giant Salamanders (Dicamptodon): Applying Null Models To Resource Partitioning, Craig A. Steele, Colin Brammer
Western North American Naturalist
We examined stomach contents of preserved specimens of larval Pacific giant salamander (Dicamptodon tenebrosus) and Cope's giant salamander (D. copei) collected from sympatric and allopatric stream populations. The dietary components of these specimens were used to calculate dietary overlap between the 2 species and to determine if changes in overlap existed between sympatric and allopatric populations. To statistically test overlap values, a randomization algorithm was used to construct a simulated data matrix (i.e., null model) in order to compare observed values of dietary overlap to a distribution of overlap values from the null model. Significant levels …
Long-Term Fire History In Great Basin Sagebrush Reconstructed From Macroscopic Charcoal In Spring Sediments, Newark Valley, Nevada, Scott Mensing, Stephanie Livingston, Pat Barker
Long-Term Fire History In Great Basin Sagebrush Reconstructed From Macroscopic Charcoal In Spring Sediments, Newark Valley, Nevada, Scott Mensing, Stephanie Livingston, Pat Barker
Western North American Naturalist
We use macroscopic charcoal analysis to reconstruct fire history in sagebrush (Artemisia tridentata var. wyomingensis and A. tridentata var. tridentata), in Newark Valley, Nevada. We analyzed charcoal at continuous 1-cm intervals (~7–127 years), and pollen at 2- to 10-cm intervals (~70–263 years) in a core spanning the last 5500 cal yr BP (calendar years before present). A charcoal peak in the historic period was associated with a >1400-ha fire dated to 1986 that burned in the watershed. We reconstructed the prehistoric fire history by inferring fires from similar charcoal peaks that were significantly greater than the background charcoal …
Aspects Of Sacramento Pikeminnow Biology In Nearshore Habitats Of The Sacramento–San Joaquin Delta, California, Matthew L. Nobriga, Frederick Feyrer, Randall D. Baxter
Aspects Of Sacramento Pikeminnow Biology In Nearshore Habitats Of The Sacramento–San Joaquin Delta, California, Matthew L. Nobriga, Frederick Feyrer, Randall D. Baxter
Western North American Naturalist
We documented distribution, relative abundance, diet composition, and body condition of Sacramento pikeminnow Ptychocheilus grandis during 2001 and 2003 at 5 sites in the Sacramento–San Joaquin Delta, California. Sacramento pikeminnow densities in nearshore habitats were higher in 2003 than 2001. In both years, spatial distribution of beach seine densities was similar. There were no significant differences in density among sampling sites except for the southernmost site where the catch was near zero. Based on rotary screw-trap data from a 6th site, we found relative abundance of Sacramento pikeminnow entering the Delta via an artificial floodplain was positively correlated with flow. …
Reproductive Characteristics Of Two Syntopic Lizard Species, Sceloporus Gadoviae And Sceloporus Jalapae (Squamata: Phrynosomatidae), From Tehuacán Valley, Puebla, México, Aurelio Ramírez-Bautista, América L. Ortíz-Cruz, Ma. Del Coro Arizmendi, Jorge Campos
Reproductive Characteristics Of Two Syntopic Lizard Species, Sceloporus Gadoviae And Sceloporus Jalapae (Squamata: Phrynosomatidae), From Tehuacán Valley, Puebla, México, Aurelio Ramírez-Bautista, América L. Ortíz-Cruz, Ma. Del Coro Arizmendi, Jorge Campos
Western North American Naturalist
We studied the reproductive characteristics of 2 syntopic lizard species, Sceloporus gadoviae and Sceloporus jalapae (Phrynosomatidae). Specimens of S. gadoviae (N = 105) and S. jalapae (N = 41) were collected in a tropical arid forest from Tehuacán Valley, Puebla, México. Males of S. gadoviae reached sexual maturity at the same snoutvent length (SVL; 45.0 mm) as S. jalapae, and a similar pattern occurred in females of both species (SVL; 41.0 and 42.0 mm, respectively). Males of S. gadoviae exhibited reproductive activity throughout the year, with a longer activity during the dry (November to May) and part …
Competitive Interactions Between Endangered Kit Foxes And Nonnative Red Foxes, Howard O. Clark Jr., Gregory D. Warrick, Brian L. Cypher, Patrick A. Kelly, Daniel F. Williams, David E. Grubbs
Competitive Interactions Between Endangered Kit Foxes And Nonnative Red Foxes, Howard O. Clark Jr., Gregory D. Warrick, Brian L. Cypher, Patrick A. Kelly, Daniel F. Williams, David E. Grubbs
Western North American Naturalist
We investigated interference and exploitative competition between endangered San Joaquin kit foxes (Vulpes macrotis mutica) and nonnative red foxes (V. vulpes). Seven kit foxes and 16 red foxes were radio-collared and tracked via radiotelemetry near Lost Hills, California. One kit fox was killed by a red fox. Home ranges of the 2 species did not overlap extensively. Although both species used similar habitats, they used different parcels of land. Kit foxes and red foxes primarily consumed rodents on the study site, and dietary overlap was considerable. Red foxes also may have been using dens formerly used …
Fish Assemblage Structure Following Impoundment Of A Great Plains River, Michael C. Quist, Wayne A. Hubert, Frank J. Rahel
Fish Assemblage Structure Following Impoundment Of A Great Plains River, Michael C. Quist, Wayne A. Hubert, Frank J. Rahel
Western North American Naturalist
Understanding the upstream and downstream effect of impoundments on stream fish assemblages is important in managing fish populations and predicting the effects of future human activities on stream ecosystems. We used information collected over a 41-year period (1960–2001) to assess changes in fish assemblage structure resulting from impoundment of the Laramie River by Grayrocks Reservoir. Prior to impoundment (i.e., 1960–1979), fish assemblages were dominated by native catostomids and cyprinids. After impoundment several exotic species (e.g., smallmouth bass [Micropterus dolomieu], walleye [Sander vitreus; formerly Stizostedion vitreum], yellow perch [Perca flavescens], brown trout [Salmo …
Notes On Significant Collections And Additions To The Flora Of Glen Canyon National Recreation Area, Utah And Arizona, Between 1992 And 2004, John R. Spence
Notes On Significant Collections And Additions To The Flora Of Glen Canyon National Recreation Area, Utah And Arizona, Between 1992 And 2004, John R. Spence
Western North American Naturalist
Symphyotrichum expansum (Puepp ex Spreng.) Nesom is reported new to Utah from the Escalante River drainage. A major range extension is reported for Aralia racemosa L. in the Escalante drainage, and additional populations are reported of the rare species Imperata brevifolia Vasey in Utah, including the 1st record for the Grand Staircase–Escalante National Monument. Heterotheca grandiflora Nutt. is reported new to north central Arizona. New locations and notes on an additional 22 rare species in Glen Canyon National Recreation Area are listed.
Dynamics Of A Dwarf Bear-Poppy (Arctomecon Humilis) Population Over A Sixteen-Year Period, K. T. Harper, Renée Van Buren
Dynamics Of A Dwarf Bear-Poppy (Arctomecon Humilis) Population Over A Sixteen-Year Period, K. T. Harper, Renée Van Buren
Western North American Naturalist
A population of the dwarf bear-poppy (Arctomecon humilis Coville, Papaveraceae) at Red Bluff, Washington County, Utah, was monitored twice annually between 1987 and 2002. This is a narrowly endemic, gypsophilous species that has been formally listed as endangered since 1979. During the 16 years of observation, density of this species has fluctuated between 3 and 1336 individuals on the 0.07-ha monitoring plot. Moderate to large recruitments of seedlings occurred in 1992, 1995, and 2001. Seedling recruitments from a large, long-lived seed bank are triggered by abundant precipitation during the February–April period. At least 5.0 cm of rainfall is required …
Fleas (Siphonaptera) In Nests Of Voles (Microtus Spp.) In Montane Habitats Of Three Regions Of Utah, Glenn E. Haas, James R. Kucera
Fleas (Siphonaptera) In Nests Of Voles (Microtus Spp.) In Montane Habitats Of Three Regions Of Utah, Glenn E. Haas, James R. Kucera
Western North American Naturalist
As a parallel study of a survey of fleas of trapped small mammals in montane southern Utah, we removed 77 adult fleas from 12 of 13 nests of voles (Microtus longicaudus, M. montanus and M. richardsoni) collected from montane meadows in the Abajo and La Sal Mountains, the Markagunt Plateau and Pine Valley Mountains, and the Uinta Mountains, May 1991–July 2002. Six species and subspecies of fleas parasitic on Microtus spp. were found, 1–3 species in each nest. Three specimens of the ubiquitous deer mouse (Peromyscus spp.) flea Aetheca wagneri (Baker) were also found. We collected the …
Effect Of Cryptobiotic Crust Type On Microarthropod Assemblages In Piñon-Juniper Woodland In Central New Mexico, S. L. Brantley, U. L. Shepherd
Effect Of Cryptobiotic Crust Type On Microarthropod Assemblages In Piñon-Juniper Woodland In Central New Mexico, S. L. Brantley, U. L. Shepherd
Western North American Naturalist
Cryptobiotic crusts make up an important part of the ground cover in arid systems. Along with their roles of retarding soil erosion and enhancing soil fertility, crusts may also be supporting local and regional arthropod biodiversity. We inventoried arthropod species in mossy, lichen, and mixed (lichen and mossy) cryptobiotic crusts at 2 sites in central New Mexico piñon-juniper habitat. We collected 240 crust samples and used a heptane flotation technique to extract the microarthropods. We found 39 species of microarthropods and small macroarthropods, with significantly fewer species on lichen. Species richness was higher in March than in August, but diversity …
Habitat Use By Brush Mice (Peromyscus Boylii) In Southeastern Arizona, Amy B. Gottesman, Michael L. Morrison, Paul R. Krausman
Habitat Use By Brush Mice (Peromyscus Boylii) In Southeastern Arizona, Amy B. Gottesman, Michael L. Morrison, Paul R. Krausman
Western North American Naturalist
No abstract provided.
Contribution To The Morphology And Descriptive Biology Of Caurinella Idahoensis (Ephemeroptera: Ephemerellidae), Luke M. Jacobus, W. P. Mccafferty
Contribution To The Morphology And Descriptive Biology Of Caurinella Idahoensis (Ephemeroptera: Ephemerellidae), Luke M. Jacobus, W. P. Mccafferty
Western North American Naturalist
Reared specimens from Bridge Creek, Idaho County, Idaho, provide the bases for the first descriptions of Caurinella idahoensis egg and alate stages and redescription of the larval stage. Larvae are distinguished from other Nearctic Ephemerellinae species by the distinctive posterolateral projections on abdominal segment 9. Male adults have a unique combination of characters associated with their genitalia. Larvae were associated with the colonial bluegreen alga Nostoc parmelioides in a clear, cold headwater stream. Several other Diptera, Ephemeroptera, Plecoptera, and Trichoptera also were found in cohabitation with C. idahoensis. Amorphous detritus appears to be a major component of the diet …
Habitat Of Three Rare Species Of Small Mammals In Juniper Woodlands Of Southwestern Wyoming, Kevin M. Rompola, Stanley H. Anderson
Habitat Of Three Rare Species Of Small Mammals In Juniper Woodlands Of Southwestern Wyoming, Kevin M. Rompola, Stanley H. Anderson
Western North American Naturalist
Southwestern Wyoming constitutes the northern limit of the ranges of the cliff chipmunk (Tamias dorsalis), pinyon mouse (Peromyscus truei), and canyon mouse (P. crinitus). In addition to trying to determine their presence in the region, we wanted to identify habitat characteristics commonly used by each of these species. We used Sherman live-traps to sample 14 sites representing 2 distinct habitat types in 1998 and 1999: juniper-rocky slopes and juniper cliffs. Seventeen habitat characteristics were measured at capture locations for each species and compared with randomly located points. Best subsets multiple logistic regression was used …
Growth In Sonoran Desert Populations Of The Common Chuckwalla (Sauromalus Obesus), Brian K. Sullivan, Matthew A. Kwiatkowski, Paul S. Hamilton
Growth In Sonoran Desert Populations Of The Common Chuckwalla (Sauromalus Obesus), Brian K. Sullivan, Matthew A. Kwiatkowski, Paul S. Hamilton
Western North American Naturalist
No abstract provided.
Population Structure And Paternity In An American Black Bear (Ursus Americanus) Population Using Microsatellite Dna, Elizabeth A. Sinclair, Hal L. Black, Keith A. Crandall
Population Structure And Paternity In An American Black Bear (Ursus Americanus) Population Using Microsatellite Dna, Elizabeth A. Sinclair, Hal L. Black, Keith A. Crandall
Western North American Naturalist
We report genetic microsatellite data from analysis of 71 American black bears (Ursus americanus) from the East Tavaputs Plateau in eastern Utah. Heterozygosity was 52.9%, which is lower than other mainland North American populations and possibly reflects low recruitment into the study area. We used a combination of known pedigrees (mother/cubs), relatedness estimates, and paternity estimation using CERVUS to infer single and possible multiple paternity within litters, breeding by pairs over consecutive years, and the possibility of a single male successfully breeding with multiple females in a single year. Estimates of inbreeding effective population size indicate the East …
Habitat Features And Predictive Habitat Modeling For The Colorado Chipmunk In Southern New Mexico, Marina Rivieccio, Bruce C. Thompson, William R. Gould, Kenneth G. Boykin
Habitat Features And Predictive Habitat Modeling For The Colorado Chipmunk In Southern New Mexico, Marina Rivieccio, Bruce C. Thompson, William R. Gould, Kenneth G. Boykin
Western North American Naturalist
Two subspecies of Colorado chipmunk (state threatened and federal species of concern) occur in southern New MeXico: Tamias quadrivittatus australis in the Organ Mountains and T. q. oscuraensis in the Oscura Mountains. We developed a GIS model of potentially suitable habitat based on vegetation and elevation features, evaluated site classifications of the GIS model, and determined vegetation and terrain features associated with chipmunk occurrence. We compared GIS model classifications with actual vegetation and elevation features measured at 37 sites. At 60 sites we measured 18 habitat variables regarding slope, aspect, tree species, shrub species, and ground cover. We used logistic …
Geobotany Of The Niobrara Chalk Barrens In Colorado: A Study Of Edaphic Endemism, Sylvia Kelso, Nathan W. Bower, Kirsten E. Heckmann, Paul M. Beardsley, Darren G. Greve
Geobotany Of The Niobrara Chalk Barrens In Colorado: A Study Of Edaphic Endemism, Sylvia Kelso, Nathan W. Bower, Kirsten E. Heckmann, Paul M. Beardsley, Darren G. Greve
Western North American Naturalist
The chalk barrens of the Niobrara Formation in the Arkansas River valley of Colorado exhibit a high degree of plant endemism and rarity. We examined their geochemistry and structure as well as the reproductive ecology of their signature species Mirabilis rotundifolius to assess factors influencing endemism. While no single component consistently identified the barren soils, the natural locations that support Mirablilis can be identified using elemental profiles from a cluster analysis of soil extracts. Because seeds germinate and plants proliferate in transplant gardens with non-calcic soils, bedrock and soil chemistry do not appear to be determinant components of endemism. Mirabilis …